1. Field of the Invention.
The present invention relates generally to sighting devices for use with an archery bow, and more particularly, but not by way of limitation, to an improved sight apparatus for an archery bow which employs an adjustable range finder in combination with a pendulum sight to compensate for elevational differences between the bow and the target.
2. Brief Description of the Related Art.
Hunters who use an archery bow and arrow must overcome several obstacles to take game consistently. These obstacles include accurately estimating range and target size and in turn positioning the bow to shoot at the proper angle of shot. Unless one possesses superior skill and instinct, a sight apparatus is normally utilized on the bow to aid the bowhunter in properly aiming the arrow at the intended target.
Many sight apparatuses have been proposed in the past. The most common type of sight apparatus utilizes a plurality of spaced apart horizontal sight pins. Each of the pins represents a particular distance. Thus, the arrow is properly aimed at a target when distance to the target is known and the corresponding pin is aligned with the target. The problem encountered is that a hunter must know the exact distance to the target or be able to accurately estimate the distance in order to use the correct sight pin.
In an attempt to increase a hunter's shooting accuracy by eliminating distance estimation, combination range finders and sights have been proposed which employ adjustable range finder pins between which the target is framed to obtain the proper shot angle. One such device is disclosed in U.S. Pat. No. 4,995,166, issued to Knemeyer. The Knemeyer patent discloses a sight pin positioned between a top range finder pin and a bottom range finder pin which are moved together or apart to frame the target. As the top and bottom range finder pins are moved to frame the target the sight pin travels along a vertical path to a position where the proper trajectory is obtained when the sight pin is aligned with the target.
While this particular device has met with some success, problems have nevertheless been encountered with use of the Knemeyer device. In particular, the linear travel path of the range finder pins do not allow the range finder pins to be easily adjusted for targets having different heights. Instead, parts must be inconveniently interchanged in order to use the device for targets of different sizes, or the archer must attempt to compromise for the difference in the height of the target by aiming higher or lower than the sight pin indicates depending on whether the target is taller or shorter than the height of the target the device is set up to shoot.
In that a hunter cannot count on game, such as deer or elk, traveling along a path to which the hunter knows the distance, and an inaccurate estimation of the distance to the target will result in missing the target, bowhunters often use equipment that causes the arrow to travel along a flatter trajectory thereby reducing the need to accurately estimate the distance to the target. Such equipment includes a bow strung at high poundage, speed cams, fast flight strings, a greater let off at full draw, and light weight arrows.
The features mentioned above have their drawbacks which a hunter may or may not wish to accept. Increased bow poundage can cause less hold time and less control. Radical cams and lighter weight arrows cause increased vibration and noise which can alert game and affect arrow flight. For these and other reasons, it is desirable to use a bow with lower poundage and heavier arrows.
Another problem encountered while hunting with an archery bow is that the hunter and the target are often not on the same horizontal plane. That is, the hunter may be positioned in a treestand or on a hillside wherein the target is positioned below the hunter. Conversely, it may be that the target is positioned above the hunter. To compensate for the difference in elevation, a class of sight commonly known as the pendulum sight has been used. Prior art pendulum sights have been limited in range due to the fact that the pivot point of the pendulum is fixed. When shooting from an elevated position of about 15 feet and at a target at relatively close range, 15 yards for example, the pendulum sight remains at true vertical thus adjusting the tilt of the bow to shoot on a flatter trajectory than required for a non-elevated shot. If the range is increased by 10 yards, the angle of the pendulum relative to the bow is changed by a certain number of degrees. Because the change in angle is significant between a distance of 15 yards and 25 yards, the pendulum sight remains fairly accurate. However, if the range is increased another 10 yard increment, the angle of change is approximately one half the previous angle of change and thus the needed movement of the pendulum drops by half. Because the angle of change is decreased with each subsequent increase in target range, the prior art pendulum sights are rendered ineffective beyond certain distances and below certain heights and thus require some type of conventional sighting system when shooting on a non-elevated plane which is operated separately from the pendulum sight.
To this end, an improved sight apparatus has long been needed which enables an archer to quickly and accurately determine the range to a target and in turn position the bow for the proper arrow trajectory regardless of the elevation between the archer and the target and which is quickly and easily adjustable for use on targets of various sizes. It is to such an improved sight apparatus that the present invention is directed.